Masters Thesis

Vertical and Latitudinal Distribution of Lottia Scabra and Lottia Conus

Cryptic species can often cause problems for baseline and ecological studies as these species are not readily identified in the field. Lottia scabra and Lottia conus form a north/south cryptic species pair where they occupy the same habitat, but L. scabra is more abundant in northern California and L. conus is more abundant in at least the southern portions of southern California. Past El Niño events have resulted in prolonged anomalous warming of coastal seawater, which may be impacting the vertical and latitudinal distribution of these two species as has been documented for another north/south pair in California, L. austrodigitalis and L. digitalis. To monitor the current and potentially changing distribution of L. conus and L. scabra, quadrat sampling was performed at nine sites in California at various heights in the mid to high intertidal, collecting a subset of limpets to identify in the lab. A range refinement of L. conus has occurred with its previous documented northern limit being Point Conception to now its current northern limit being Jalama Beach, CA. A transition zone occurs from San Pedro to Jalama Beach where L. conus becomes less abundant and L. scabra becomes more abundant. With an established baseline, future studies may document whether this distribution changes in response to temperature variations from climate change or El Niño events. Susceptibility to temperature changes may make limpets good indicator species for detecting regional climate change effects in the intertidal as well as potential model species for future studies to use when observing rocky intertidal habitats.

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